Cartridge-type filters for swimming pools, hot tubs, spas and the like are well known in the art. Chemical treatment of pool water with sanitizing media such as bactericides, germicides or algaecides is also known in the art. Combinations of cartridge-type filters and chemical treatment are limited in the art.
U.S. Pat. No. 4,780,197 combines a cartridge filter with a chlorination module, but only a partial flow is directly in contact with the chemical treatment media. Even the insertion of a "tea bag" type apparatus filled with sanitizing media, as disclosed in U.S. Pat. No. 4,416,854, into the interior of a cartridge-type filter would not insure contact of the full flow through the filter with the sanitizing media. A need exists for a combination of a cartridge-type filter and sanitizing treatment, whereby the full system flow through the filter is directly in contact with the sanitizing media.